When it comes to MLB's top prospects, no position is more volatile than pitcher. Whether it's injury, inconsistency, or being exposed at the major league level, opinions on rookie pitchers can change in a hurry, which makes it tough for fantasy baseball owners to track sleepers and discern between who's worth drafting/picking up on the waiver wire and who isn't.

Below is a list of the key names you might need to know as we head toward opening day and the rest of the 2017 season. It never hurts to be armed with as many names as possible, as even just a short stretch of good starts can yield fantasy value.

Top Baseball Prospects 2017: Pitcher

The Pirates have three rookies in the mix for rotation spots this Spring. Righthander Tyler Glasnow has the dominant stuff (plus mid-90s fastball, plus excellent curve, solid change) of a No. 1 starter and performed adequately in a late-season call-up last year (4.24 ERA, 9.4 K/9 in 23 innings). However, he has shown inconsistent command and may need more seasoning. Lefthander Steven Brault also saw big league time last year but wasn’t as effective (4.86 ERA, 12.3 H/9 in 33 innings) and shows mostly average stuff. Righthander Trevor Williams is a third rookie who made his debut last year and is in the mix for a starting spot in 2017. Williams pitches off a sinker-slider combo but doesn’t have the stuff to miss many bats.

If Glasnow secures a spot, he should win 10-plus games, post an average ERA and below-average WHIP, and strike out more than a batter per inning. Long-term he needs to improve his command to reach his potential as a bona fide frontline starter. Brault has less projection and should post back-of-the-rotation starter numbers, while Williams would probably have a hard time holding the job for more than a month or two.

Robert Gsellman (RHP, New York Mets) was a revelation last season in 45 big league innings (2.42 ERA, 42/15 K/BB) and now is in a battle for a full-time rotation spot this spring. Gsellman works off a bowling-ball sinker that he pairs with an above-average slider to generate lots of ground balls and whiffs. He’s not the ace he appeared to be last season, but he’s a solid mid-rotation guy. If he opens the season in the majors, he should win 10-12 games, post above-average ratios, and strike out close to a batter per inning.

The Reds have three rotation spots up for grabs this spring and there are five rookies left in the mix. LHP Amir Garrett, RHP Robert Stephenson, LHP Cody Reed, RHP Rookie Davis, and LHP Sal Romano are joined by Tim Adleman and veteran Bronson Arroyo in a competition for the three spots. Garrett, Reed, and Stephenson have the most upside, but all three have been average thus far in big league camp.

Reed has a plus mid-90’s fastball and a nasty slider, but he looked tentative in a 2016 call-up (7.36 ERA and 67 hits allowed in 48 innings). If he can trust his stuff and improve his command, he has the tools to be a No. 2 or No. 3 starter, but his inconsistency makes him a risky bet right now. Garrett is a former college basketball player who is still developing as a pitcher and probably needs more seasoning. At his best, Garrett has a plus low-90’s fastball, a slider that he’ll use in any count, and a solid changeup. His command and pitch execution are inconsistent, but his stuff is hard to square up (only 99 hits allowed in 144.2 innings between Double-A and Triple-A last season). If he can execute his pitches more consistently, he has the stuff to be a No. 2 starter. Stephenson has three above-average pitches, but his command is below-average and this looks like a make-or-break season for the former top prospect. He struggled in a big league call-up last year (6.08 ERA and 19 walks in 37 innings) and will probably end up in the bullpen if he doesn’t throw more strikes this season.

Romano has looked the best of the five in big league camp this spring and could nab a rotation spot despite having spent all of last year at Double-A (3.52 ERA, 144/34 K/BB in 156 innings). Romano has a plus mid-90’s fastball, nasty slider, and developing change. He attacks the strike zone and can miss bats. If he can improve his change and keep his aggressive attitude against more advanced hitters, Romano could be a solid mid-rotation starter who will post above-average ratios and log plenty of K’s. Davis is the least likely to win a spot, but he’s a serviceable backend starter with a low-90’s fastball and a deep repertoire that he commands well.

The Rockies have five rookies among the six hurlers competing for two open rotation spots. RHP Jeff Hoffman looked to be a frontrunner for one of those spots despite an inconsistent major league debut in 2016 (4.88 ERA and 22/17 K/BB in 31.1 innings), but his inconsistency has carried over to the spring and he might open the season back in the minors. Hoffman has plus stuff (mid-90s fastball, above-average curve, solid changeup) and the potential to be a No. 3 starter, but he hasn’t mixed or located well enough to keep hitters off balance.

RHP German Marquez also struggled in a 2016 call-up (5.23 ERA in 21 innings), but he has good command of three pitches, including a plus mid-90’s fastball. Marquez has not pitched well in big league camp and might head back to Triple-A this year, but he has the tools to be a No. 4 starter in the majors. RHP Antonio Senzatela has performed well this spring and has gone from an afterthought to a serious rotation candidate. Senzatela throws strikes, locates well, and mixes three pitches. He missed time last season with shoulder soreness, but he has been healthy this year and looks ready to fulfill his potential as a solid mid-rotation starter. If he wins a spot he’ll post a good WHIP while logging average strikeout totals.

LHP Kyle Freeland spent half of last season at Triple-A, where he put up average numbers (3.91 ERA, 57/19 K/BB in 74 innings). At his best Freeland pitches off an above-average fastball and plus slider. His command is good, but he needs to improve his change to succeed as a big league starter. Until his changeup improves, he’s a risky bet to put up even average numbers. RHP Harrison Musgrave is the final rookie candidate, but he’ll have a hard time sticking in the rotation. Musgrave has fringe-average stuff, including a 90-mph fastball, and looks more like a bullpen guy than a big league starter. He posted solid numbers last year at Triple-A (4.30 ERA, 79/40 K/BB in 113 innings) and would probably log similar, but slightly worse, stats with the Rockies.

Jharel Cotton (RHP, Oakland) has pitched well this spring and should open the season in Oakland’s starting rotation. Cotton looked good in a late-season call-up (2.15 ERA, 23/4 K/BB in 29 big league innings) and appears to be a solid mid-rotation guy. He’s underrated due to his 5-11 stature, but he has solid command of four pitches, including a plus change and a low-90s fastball. He won’t win lots of games pitching for the A’s, but he should post good ratios and average strikeout totals.

Ty Blach (LHP, San Francisco) is battling with Matt Cain for the Giants’No. 5 spot, but he could also end up in the big league bullpen to open the season. Blach pitched well in 17 innings (1.06 ERA, only eight hits allowed) with the Giants last season but his stuff is average. He commands all his pitches and mixes his offerings to keep hitters off balance, but he’ll struggle to be more than a back-end starter who puts up average numbers.

Luke Weaver (RHP, St. Louis) is competing for a back-end rotation spot after posting a 5.70 ERA with 45 strikeouts in 36 innings with the Cardinals last year. Weaver has plus command of a low-90s fastball with lots of movement and an above-average change. He has been sidelined with back stiffness this spring but could open the season in the majors if he can stay healthy. Weaver profiles as a mid-rotation starter who will post above-average strikeout totals.

The Twins have two rookies among the half dozen guys competing for the No. 5 starter spot this spring. LHP Adalberto Mejia was acquired from the Giants last season and has impressed in big league camp. Mejia is a polished hurler with good command of three above-average pitches. He doesn’t have lots of upside, but he has a high floor and should produce average numbers if he wins a starting role. RHP Justin Hurley was a Rule 5 pick this offseason and could end up in the bullpen if he doesn’t win a rotation spot. Hurley mixes four pitches and has good command, but his stuff is average and he projects more as a long reliever than a big league starter.

Alex Meyer (RHP, Los Angeles Angels) is competing to be the Angels’ No. 5 starter. He’s had an up-and-down spring, but the Angels like his stuff and would love to have the big fire-baller in their rotation after he performed adequately in a five-start call-up last season. Meyer has a high-90s fastball and solid off-speed stuff, but he’s been held back by poor control. The Angels have attempted to tweak his mechanics, but he’s still not very consistent. If he wins a rotation spot, Meyer should win a few games, post below-average ratios, and strike out roughly a batter per inning.

Mike Hauschild (RHP, Texas) was an offseason Rule 5 pick from the Astros and now has a strong chance to win a rotation spot with the Rangers. Hauschild has good command of average stuff, including a low-90s fastball, slider, and change. He locates well and pitches effectively down in the zone. His upside is that of a back-end starter, but his command and ability to mix pitches should allow him to be effective as a rookie. If he wins the job, expect solid, if unspectacular, numbers.

The Orioles’ Chris Lee (LHP) and Gabriel Ynoa (RHP) are competing to replace starter Chris Tillman, who has been sidelined with a shoulder injury. Neither projects as more than a back-end starter, but either could be effective as a fill-in option. Lee throws a sinker, slider, and change, which generate lots of ground balls. He’s not overpowering, but he locates well and induces weak contact. Ynoa has a similar profile with a fastball that’s slightly better and command that’s not as good. Neither will strike out many batters, but they might win a few games if Tillman is sidelined for more than a few weeks.

Fantasy Baseball Sleepers: Keeper league pitchers

Righthanders Lucas Giolito, Reynaldo Lopez, and Carson Fulmer all have gotten plenty of innings in big league camp for the White Sox, but they will almost certainly begin the season in the minors. However, it’s likely that all three will see major league time in 2017. Giolito has the most upside with electric stuff, including a mid-to-upper-90’s fastball and a nasty 12-6 curve. He experienced a rocky big league debut with the Nationals in late 2016 (6.75 ERA and only 11 strikeouts in 21.1 innings) and he’s been inconsistent this spring, but the South Siders have one of the best pitching development staffs in baseball and should be able to right Giolito’s ship. If he can improve his command and refine his changeup, Giolito has the tools to be a front-line starter.

Lopez also saw time with the Nationals last season (4.91 ERA with 42 strikeouts in 44 innings) and has had a rough spring. At his best, Lopez pitches off a mid-90’s fastball that can reach triple digits. His above-average mid-70’s curveball is a solid second offering, and his high-80’s change flashes plus with good sink and arm-side fade. He should also benefit from the Sox player development ability, and, if he can improve his command, he has the stuff to be a No. 2 starter.

Fulmer has the most uncertain future of the three due to ongoing struggles with his command. He has three above-average pitches, including a solid low-90’s fastball, but his jerky delivery has made it hard for him to execute his stuff consistently. If Fulmer can improve his command, he profiles as a mid-rotation starter. If not, he’ll probably make his way to Chicago via the bullpen.

Rays righthanders Brent Honeywell, Jose De Leon, and Jacob Faria will open the season in the minors, but all three could see major league time during 2017. De Leon is closer to the majors – he started four games for the Dodgers last season – but Honeywell has more upside. Honeywell’s smooth mechanics result in above-average command of four pitches. His plus screwball is his best pitch, but his low-90s fastball and above-average changeup are also effective weapons. He’s at least a No. 3 starter with the potential to better than that if it all comes together. De Leon dominated Triple-A hitters in 2016 (111/20 K/BB in 86.1 innings) with a low to mid-90s fastball, a plus changeup, and a solid slider. He should eventually slot in as a mid-rotation starter. Faria has average stuff and profiles as a back-end starter with average command.

Josh Hader (LHP, Milwaukee) was optioned to minor league camp, but he pitched well in big league camp this spring and could rejoin the club at some point in 2017. At his best, Hader dominates hitters with an explosive fastball, wipeout slider, and nasty low three-quarters release point. Hader struggled with command and altitude at Triple-A Colorado Springs, and he doesn’t yet have the consistency to be a big league starter. If he can tighten his command and improve his changeup, he could be a No. 2 or 3 starter. If not, he’ll end up in the bullpen as a dominant lefty specialist.

The Yankees’ RHP Chad Green is officially still a candidate to win one of New York’s two final rotation spots, but it’s looking more likely that he’ll begin the season in Triple-A. Green pitched adequately in 46 big league innings last year (4.73 ERA, 52/15 K/BB) and profiles as a serviceable back-end starter with his mid-90s fastball and hard slider. He could also end up in the big league bullpen if the Yankees’ rotation stays healthy. RHP James Kaprielian is further away from the majors, but he returned from injury last season to post dominant numbers at High-A and then pitched well in the Arizona Fall League. At his best, Kaprielian has solid command of four quality pitches, including a plus mid-90’s fastball. If he stays healthy he has the chance to get a midseason call-up and profiles as a solid No. 3 starter who will post above-average strikeout totals.

The Astros have a top-notch starting rotation, but they also two big arms who could step in if one of the current starters were to go down with an injury. Righthanders Francis Martes and David Paulino both will probably open the season at Triple-A. Paulino has excellent stuff, including a mid-90s fastball, a plus curve, and a solid change, but he’s inconsistent and doesn’t always command the ball well in the strike zone. Martes also has great stuff – a plus fastball with good movement, an above-average change, and a breaking ball that flashes plus – and also suffers from occasional lapses of command. Paulino is closer to the bigs, but Martes has greater upside and both guys will need to be more consistent to reach their potential as No. 2 starters.

Frankie Montas (RHP, Oakland) won’t make the Athletics’ rotation out of spring training, but he could finish the season in Oakland. Montas has a high-90s fastball, an above-average slider, and a developing change. His command is average, but his stuff is good enough to make up for less than perfect location. He profiles as a mid-rotation guy and could eventually fill that role for the A’s sometime this year.

Tyler Beede (RHP, San Francisco) improved his command and expanded his arsenal in a solid 2016 campaign at Double-A (2.81 ERA, 135 strikeouts in 147 innings). He has pitched well so far in big league camp and could be in line for a call-up sometime this season. Beede throws five pitches, including a low-90s fastball than can tick up and an above-average curve. His command is average, but his stuff is good enough to profile as a mid-rotation starter.

Sean Newcomb (LHP, ATL) has been up and down prospect lists for several years. His plus stuff (mid-90s fastball, curve that flashes plus, solid change) pushes him up, and then his poor command (4.6 BB/9 last year) pushes him down. He’ll open the season in Triple-A and wait for the call. If he can throw more strikes, he profiles as a mid-rotation starter. If he can’t, he’ll end up in the bullpen.

Anthony Banda (LHP, Arizona) will begin the season in the minors, but he’s a polished hurler who’s close to big league ready. Banda has a smooth, repeatable delivery and gets good extension at his release point. His best pitch is a plus curve but he also has an above-average low-90s fastball and effective change. The D-backs will probably need rotation help at some point in 2017, and Banda fits the bill as a quality mid-rotation guy.

The Royals’ Josh Staumont and Kyle Zimmer will open the year in the minors, but both could get a call-up before 2017 is over. Staumont has a fastball that can reach triple digits and has posted a 12.4 K/9 in 163 minor league innings. His delivery can be inconsistent and his changeup needs work, but he has the tools to be a No. 2 or 3 starter in the bigs. A former top-ranked prospect, Zimmer has been plagued by injuries and hasn’t yet pitched a full season since being drafted in the first round in 2012. He has excellent stuff (good command of two plus pitches) and was healthy enough to pitch a few innings in big league camp, but he’ll need to shake off the rust and show he can stay healthy in order to get a shot. If he can stay on the field and recover his stuff, he also has the potential to be a No. 2 or 3 starter.